Please note that a very old bug (#76548) has been fixed in 7.2.8.Previously, pg_fetch_result did not fetch the next row if $row was omitted.It is now well the case, so bad use of the function can now cause some bugs in your codes.
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
pg_fetch_result — 从结果实例返回值
resultPgSql\Result 实例，由 pg_query()、pg_query_params() 或者 pg_execute()（等）返回。
row要获取的结果中的行号。行从 0 向上编号。如果省略，则获取下一行。
field
布尔值返回为 "t" 或 "f"。所有其它类型，包括数组，都以字符串形式返回，其格式与 psql
程序中的 PostgreSQL 默认方式相同。数据库 NULL 值作为 null 返回。
如果 row 超过集合中的行数或任何其他错误，则返回 false。
| 版本 | 说明 |
|---|---|
| 8.3.0 |
row 现在可为 null。
|
| 8.1.0 |
现在 result 参数接受 PgSql\Result
实例，之前接受 resource。
|
示例 #1 pg_fetch_result() 示例
<?php
$db = pg_connect("dbname=users user=me");
$res = pg_query($db, "SELECT 1 UNION ALL SELECT 2");
$val = pg_fetch_result($res, 1, 0);
echo "First field in the second row is: ", $val, "\n";
?>以上示例会输出：
First field in the second row is: 2
Please note that a very old bug (#76548) has been fixed in 7.2.8.Previously, pg_fetch_result did not fetch the next row if $row was omitted.It is now well the case, so bad use of the function can now cause some bugs in your codes.Comment on boolean fields:If you retrieve a boolean value from the PostgreSQL database, be aware that the value returned will be either the character 't' or the character 'f', not an integer. So, the statement if (pg_fetch_result($rsRecords,0,'blnTrueFalseField')) { echo "TRUE"; } else { echo "FALSE"; }will echo "TRUE" in either case (True or False stored in the field). In order to work as expected, do this instead: if (pg_fetch_result($rsRecords,0,'blnTrueFalseField') == 't') { echo "TRUE"; } else { echo "FALSE"; }See bug #33809 http://bugs.php.net/bug.php?id=33809Whether this really is a bug or a feature is not clear.However, it is probably best to always put your column names in extra quotes.$res = pg_query(...);$colname = pg_field_name($res, $j);pg_fetch_result($res, $i, "\"$colname\"");In order to use upper case in pg_fetch_result column names, it is apparently necessary to include explicit quotation marks.Thus when I do this sort of thing:$res = pg_query(...);$ncols = pg_num_fields($res);for ($j = 0; $j < $ncols; ++$j) { $colname[$j] = pg_field_name($res, $j); $name = htmlspecialchars($colname[$j]); print("Column $j name = \"$name\"\n"); $value = htmlspecialchars(pg_fetch_result($res, 0, $colname[$j])); print("Column \"{$colname[$j]}\" value = \"$value\"\n"); }I get this sort of thing:[....]Warning: pg_fetch_result() [function.pg-fetch-result]: Bad column offset specified in /.../view.php on line 247Column 8 name = "VEC index"Column "VEC index" value = ""But if I change the $value line to this:$value = htmlspecialchars(pg_fetch_result($res, 0, "\"$colname[$j]\""));I get this:[...]Column 8 name = "VEC index"Column "VEC index" value[0] = "47"In my opinion, pg_fetch_result(...) should use the quotes already. In other words, this may be a bug in the PHP postgres library. It does not seem to be a documented feature of pg_fetch_result() although the postgresql manual documents it under "SQL syntax", "Lexical structure".PHP version 5.1.4.psql version 8.1.4.Use can use pg_fetch_result when getting a value (like a smallint as in this example) returned by your stored procedure <?php$pgConnection = pg_connect("dbname=users user=me");$userNameToCheckFor = "metal";$result = pg_query($pgConnection, "SELECT howManyUsersHaveThisName('$userNameToCheckFor')");$count = pg_fetch_result($result, 0, 'howManyUsersHaveThisName');?>